irmemory: Always (try to) climb to the base address in _get_alias_relation().
irmemory: Always (try to) climb to the base address in _get_alias_relation().

This fixes opt/loadstore8.c.
Though it does not correct all cases.
More work is needed here.

jonashaag/libfirm,MatzeB/libfirm,MatzeB/libfirm,jonashaag/libfirm,jonashaag/libfirm,jonashaag/libfirm,MatzeB/libfirm,jonashaag/libfirm,jonashaag/libfirm,libfirm/libfirm,MatzeB/libfirm,libfirm/libfirm,MatzeB/libfirm,jonashaag/libfirm,libfirm/libfirm,libfirm/libfirm,MatzeB/libfirm,libfirm/libfirm,MatzeB/libfirm